The invention relates to a method for producing a cavity in a stator of an eccentric screw pump, wherein material is removed with a tool on the inside of a stator blank.
The invention also relates to a device for carrying out the method.
Methods of the type stated above are known from the prior art.
Eccentric screw pumps are used for, among other things, continuously conveying viscous fluids. They have a stator and therein rotatably supported a rotor that is helically wound such that when producing a stator for an eccentric screw pump, a helically wound cavity with a respective interior wall structure is worked into the stator blank.
A conventional method for producing a stator provides that initially a stator blank is prepared, which is then machined, for example, to form a desired interior wall structure. Machining becomes increasingly difficult as the axial length of the stator to be produced increases, in particular because conventional machining devices are not able to absorb the transverse forces that occur during the machining process without an elastic deformation of the machining device occurring perpendicular to its longitudinal extent. Precise machining of stator blanks is thus not always ensured because of this deformation.
Other methods for producing stators for eccentric screw pumps are electrical or electrochemical removal processes such as electrical erosion or electrochemical erosion. In particular, stators made of metallic materials have been produced within the scope of these methods. However, additional heat is generated with electrochemical erosion causing an undesirable tapered borehole after cool-down.
A major disadvantage in connection with all conventional methods for producing a stator for an eccentric screw pump is that only relatively short stators can be produced, or that several stator segments must be combined for a sufficiently long stator, which in turn is cost-intensive and requires additional design effort.